chapter 07_the at-line selection event (sy-lisel vs. hide)

IBM Global Business Services

© IBM Corporation 2013The AT LINE-SELECTION Event (SY-LISEL vs. HIDE) |

Dec-2008

The AT LINE-SELECTION Event (SY-LISEL vs. HIDE)


© IBM Corporation 20132 Dec-2008The AT LINE-SELECTION Event (SY-LISEL vs. HIDE) |

Objectives

The participants will be able to : Create drill-down screen.

Use AT LINE-SELECTION Event.

Apply SY-LISEL system field.

Apply the HIDE statement.

Interpret the HIDE memory.



A “Drill Down” Screen

First the user double-clicks on a record.

Then a “drill down” list is created showing data relevant to the record

initially selected by the user.



The Challenges

Second Challenge:

How is this record sent back as criteria to an ABAP SELECT statement?

First Challenge:

How did the ABAP code “know” when and which record the user has selected?

SELECT * FROM BSIK WHERE LIFNR = <selected vendor number>.



Illustration : (The AT LINE-SELECTION Event)

A New ABAPEvent

SYNTAX: AT LINE-SELECTION.

Determining When the User Is Requesting Additional Information

When the user double-clicks a line in the report, the “AT LINE-SELECTION” event occurs

(because the PICK function code is invoked).



The SY-LISEL System Field

A New ABAP

System Field

The Contents of SY-LISEL:

222 Express Vendor Inc CHICAGO

SYSTEM FIELD: SY-LISEL

When the user selects a line in the report, SY-LISEL is updated with the text from

that line.

Determining Which Records the User Is Requesting Additional Information Upon



DATA:WA_LFA1 TYPE LFA1.START-OF-SELECTION.

SELECT * FROM LFA1 INTO WA_LFA1.WRITE: / WA_LFA1-LIFNR, WA_LFA1-NAME1, WA_LFA1-ORT01.

ENDSELECT.

SELECT *

SY-SUBRCCHECK

Coding Example : AT LINE-SELECTION and SY-LISEL

This code is continued on the next page.



*--------begin of AT LINE-SELECTION event------------------------*

AT LINE-SELECTION.CHECK SY-LSIND = 1.WINDOW STARTING AT 10 4 ENDING AT 77 12.WRITE: / ‘The user double-clicked on a line in the report’.WRITE: / SY-LISEL.

*---------end of AT LINE-SELECTION event--------------------------*

Coding Example : AT LINE-SELECTION and SY-LISEL



AT LINE-SELECTION and SY-LISEL

First double-click on a record.

Then a second “drill down” list is created showing data relevant to the

record you had initially selected.

If you double-click here, will another drill window appear? Why

or why not?



Limitations of the SY-LISEL System Field

The contents of SY-LISEL:

“100141 A B Anders Heidelberg”

We can’t send an entire string to an ABAP SELECT statement.

SELECT * FROM BSIK WHERE LIFNR = 100141

However, if we could somehow send only individual fields from the selected record, we would then process that data with an ABAP

SELECT statement.100141



Demonstration

Use of AT LINE-SELECTION event and SY-LISEL system field.



Practice

Use of AT LINE-SELECTION event and SY-LISEL system field.



The HIDE ABAP Reserved Word

SYNTAX: HIDE <program field>.SYNTAX: HIDE <program field>.

START-OF-SELECTION.SELECT * FROM LFA1 INTO WA_LFA1.

WRITE: / WA_LFA1-LIFNR, WA_LFA1-NAME1, WA_LFA1-ORT01.HIDE: WA_LFA1-LIFNR.

ENDSELECT.

A New ABAP

ReservedWord

Extracting Individual Fields from the Record Chosen by the User

SELECT *

SY-SUBRCCHECK



LFA1 WORK AREA

RECORD # 2WRITE: /WRITE: / HIDE

LIST MEMORY


WRITE: / WA_LFA1-LIFNR, WA_LFA1-NAME1, WA_LFA1-ORT01.HIDE: WA_LFA1-LIFNR.

ENDSELECT.

SELECT *

SY-SUBRCCHECK

The HIDE Memory Area




WRITE: / WA_LFA1-LIFNR, . . . HIDE: WA_LFA1-LIFNR.

ENDSELECT.

MEMORY

WA_LFA1-LIFNR ---- ----VEND011VEND012VEND013

INDEX12345

This is what the HIDE memory area and work area WA_LFA1 look like after the SELECT statement above has finished

processing.

LFA1 WORK AREA

RECORD # 3

SELECT *

SY-SUBRCCHECK

The HIDE Memory Area : (Showing the Index)




WRITE: / WA_LFA1-LIFNR, WA_LFA1-NAME1, WA_LFA1-ORT01. HIDE: WA_LFA1-LIFNR, WA_LFA1-TELF1.

ENDSELECT.

HIDE MEMORY


INDEX12345

WA_LFA1-TELF1 ---- ----555-1111555-2222555-3333

If we used the HIDE statement to hide both LIFNR and TELF1, our

HIDE memory area would look like this.

SELECT *

SY-SUBRCCHECK

The HIDE Memory Area : (with More than One Field Stored)



The HIDE Index Numbers

VEND012VEND012

INDEX1234

MEMORY

WORK AREA WORK AREA WA_LFA1WA_LFA1

LINE 4 from the screen corresponds LINE 4 from the screen corresponds with INDEX 4 from the HIDE memory area.with INDEX 4 from the HIDE memory area.

The Correlation between the HIDE Memory Area and Line NumbersThe Correlation between the HIDE Memory Area and Line Numbers


INDEX12345



REPORT Y190XX02.DATA: WA_LFA1 TYPE LFA1 , WA_BSIK TYPE BSIK.


WRITE: / WA_LFA1-LIFNR, WA_LFA1-NAME1, WA_LFA1-ORT01.HIDE: WA_LFA1-LIFNR, WA_LFA1-TELF1.

ENDSELECT.

SELECT * SY-SUBRCCHECK

Coding Example : Using the HIDE ABAP Reserved Word



What Happens When the System Hides Values?

DATASOURCE

field string

TABLE WORK AREA

HIDE MEMORYWA_LFA1-LIFNR ---- ----VEND011VEND012VEND013

INDEX12345

BASIC LIST

1 (header)2 (uline)3 VEND011 Star Craft Metal4 VEND012 Quality Fabr.5 VEND013 Euro Output SA

WA_LFA1-TELF1 ---- ----555-1111555-2222555-3333

SELECT

WRITE

HIDE



What Happens When the User Selects a Valid Line?

data available for further processing

TABLE WORK AREA(Field String)


INDEX12345

BASIC LIST

WA_LFA1-TELF1 ---- ----555-1111555-2222555-3333

VEND 011

555-1111

OldData

OldData

OldData

OldData

OldData

OldData

OldData

OldData

OldData




LFA1 WORK AREALFA1 WORK AREALFA1 WORK AREALFA1 WORK AREA

?

AT LINE-SELECTION.CHECK SY-LSIND = 1.WINDOW STARTING AT 10 4

ENDING AT 77 12.SELECT * FROM BSIK INTO WA_BSIK WHERE

LIFNR = WA_LFA1-LIFNR.WRITE: / WA_LFA1-LIFNR, WA_BSIK-BELNR.

ENDSELECT.IF SY-SUBRC <> 0.WRITE: / ‘No invoices for vendor’, WA_LFA1-LIFNR.ENDIF.

Remember... This is Remember... This is referencing the program referencing the program field! The value of this field! The value of this field is dependent upon field is dependent upon which line you double-which line you double-

clicked in the on-screen clicked in the on-screen report.report.

Remember... This is Remember... This is referencing the program referencing the program field! The value of this field! The value of this field is dependent upon field is dependent upon which line you double-which line you double-

clicked in the on-screen clicked in the on-screen report.report.

SELECT *

Coding Example : Using the HIDE Memory Area



Demonstration

Usage of HIDE command in Interactive Reporting.



Practice

Usage of HIDE command in Interactive Reporting.



Challenges Revisited

Second Challenge:Second Challenge:

How is this record sent back as criteria to an How is this record sent back as criteria to an ABAP SELECT statement?ABAP SELECT statement?

METHOD: HIDE memory area.METHOD: HIDE memory area.

First Challenge:First Challenge:

How did the ABAP code “know” which record the user How did the ABAP code “know” which record the user has selected?has selected?

METHOD: When a user event is triggered, the system METHOD: When a user event is triggered, the system automatically records the line selected (via SY-LISEL automatically records the line selected (via SY-LISEL and other system fields).and other system fields).



Restart the program and double-click on the header.

Is the User Selecting a Valid Line in the Report?



Restart the program and double-click on the header. What happens?

Where does this data come from?

Is the User Selecting a Valid Line in the Report?



What Happens When the User Clicks on an Invalid Line First?

No values are restored from HIDE into program fields.The last record selected by the “SELECT” statement is still in

work area and still available for further processing.


INDEX12345

BASIC LIST

WA_LFA1-TELF1 ---- ----555-1111555-2222555-3333

VEND- OR2

555-9898 PA USA 19103

Mr. Jones $100

NET 30Phila.

123Main

Bacon Inc.




SYNTAX: END-OF-SELECTION.

A New ABAPEvent

After all of the other system events have been

executed . . .

INITIALIZATION.

AT SELECTION-SCREEN.

START-OF-SELECTION.

GET <table>.

GET <table> LATE.

. . . before the basic list is displayed.

. . . the END-OF-SELECTION event occurs . . .

The END-OF-SELECTION Event



END-OF-SELECTION.CLEAR WA_LFA1-LIFNR.

AT LINE-SELECTION.CHECK SY-LSIND = 1.CHECK NOT WA_LFA1-LIFNR IS INITIAL.WINDOW STARTING AT 10 4



ENDSELECT.IF SY-SUBRC <> 0.

WRITE: / ‘No invoices for vendor’, WA_LFA1-LIFNR.ENDIF.

2

First: Initialise the WA_LFA1-LIFNR program field just before the basic list is displayed.

Second: Make sure the WA_LFA1-LIFNR program field is not initial before processing the rest of the user event (i.e. make sure the user selected a valid line).

SELECT *

1

Part I - Initializing Fields before Basic List Displayed

Handling Invalid Line Selection



Click on a Valid Line First

data available for further processing


HIDE MEMORY


INDEX12345

WA_LFA1-TELF1 ---- ----555-1111555-2222555-3333

VEND 012

555-2222


OldData

OldData

OldData

OldData

OldData

OldData

OldData

OldData

OldData

BASIC LIST



… Then Click on an Invalid Line


No values restored from HIDE into program fields. Values restored from last valid line selected by the user are still in the work area.

HIDE MEMORY


INDEX12345

WA_LFA1-TELF1 ---- ----

555-1111555-2222555-3333

VEND 012

555-2222


OldData

OldData

OldData

OldData

OldData

OldData

OldData

OldData

OldData

BASIC LIST



Handling Invalid Line Selection

END-OF-SELECTION.CLEAR WA_LFA1-LIFNR.

AT LINE-SELECTION.CHECK SY-LSIND = 1.CHECK NOT WA_LFA1-LIFNR IS INITIAL.WINDOW STARTING AT 10 4



ENDSELECT.IF SY-SUBRC <> 0.

WRITE: / ‘No invoices for vendor’, WA_LFA1-LIFNR.ENDIF.CLEAR WA_LFA1-LIFNR.

2

1

First: Initialise the WA_LFA1-LIFNR program field just before the detail list is displayed.

Second: Make sure the WA_LFA1-LIFNR program field is not initial before processing the rest of the user event (i.e. make sure the user selected a valid line).

SELECT *

Part II - Initializing Fields after Each Use



Flow of Data

DATASOURCE

BASICLIST

HIDEMEMORY

WORK AREA



Summary

AT LINE-SELECTION event is triggered when a user double-clicks on a line in the list (or single-clicks on a line and clicks on CHOOSE button or presses F2).

System field SY-LISEL contains the contents of the line selected by the user and SY-LILLI contains the number of the line selected.

HIDE memory area exists for each lists in a report. This area gets populated with the program fields when the system encounters the HIDE statement.

Specific fields can be stored in the memory using HIDE statement. HIDE command can be used to place multiple fields in HIDE memory area.

HIDE memory area cannot be directly accessed using an ABAP statement. Information is fetched from this area depending on the line the user selects.



Question

Which system field contains the content of the selected line ?

What does a HIDE statement do ?

How is the HIDE statement used for producing detail lists ?

What is an invalid line in the context of drill down reporting ?

How do you determine if the user has clicked on a valid line ?

What records are stored in a HIDE memory area ? How do the system get the value for a particular field for the selected line from HIDE memory area ?

chapter 07_the at-line selection event (sy-lisel vs. hide)

Documents